1. Field of the Invention
The present invention relates to a communication system which is preferably adopted in a communication between a programable controller of an industrial robot and various kinds of input and output units, for example.
2. Description of the Prior Art
In the prior art, in operating an industrial robot for example, the communication between a programable controller included in the robot and input/output units comprising one or more limit switches and/or solenoid valves was performed by means of communication systems as follows.